This invention relates to a machine for bending elongate work such as reinforcing steel rods into a desired angle. More specifically, the invention is directed to improvements in or relating to such a bending machine of the portable class, suitable for transportation from one site of construction to another.
The portable bending machine has been known which has a boxlike casing complete with retractable or foldable handles for the ease of transportation. The top plate of the casing has formed therein an arcuate slot through which an upstanding bending shaft extends with clearance. The bending shaft has a bending roll rotatably mounted on its exposed top end. A fulcrum roll is rotatably mounted on the top of the casing, in a position at which the arcuate slot is centered. Also mounted on the top of the casing is an adjustable abutment for bearing against the work being bent.
A reinforcing steel rod to be bent is to be laid horizontally on the top of the casing, in a position between bending roll and fulcrum roll. The steel rod will be bent by the bending roll around the fulcrum roll as the bending roll travels from one extremity of the arcuate slot toward the other. An electric motor is normally employed in combination with a driving gear train for revolving the bending roll around the fulcrum roll.
A problem has arisen with such a bending machine of conventional make, as the drive motor and the various shafts have so far been mounted, either directly or indirectly, to the top, bottom, and side walls of the casing. One known construction employed a horizontal mounting platform within the casing, with the opposite ends of the platform welded to the side walls of the casing. Some of the shafts were rotatably supported, each at one end, on the platform. Another construction is known in which some rotary shafts were rotatably mounted on the bottom wall of the casing.
The mounting of the various working parts of the bending machine to the side and bottom walls of the casing, in addition to its top plate, is objectionable for several reasons. First, the casing itself had to be of complex construction to permit the mounting of such working parts to its top, bottom and side walls. Second, not only the top but also the bottom and side walls of the casing had to be sufficiently thick and sturdy to firmly hold the working parts in their relative positions, thus adding considerably to the total weight of the machine. Third, difficulties were encountered in mounting some components, notably the drive motor and the associated gear train, within the casing in good working order.
Finally, but not least importantly, elongate shafts were needed according to the conventional mounting methods. Being subject to great bending stresses, such elongate shafts had to be large in diameter, again adding to the total weight of the machine.